I. Field of the Invention
This invention relates generally to electronic transducers for use in monitoring snoring episodes during sleep studies, and more particularly to a transducer especially designed to be worn on the nose for producing an electrical output proportional to vibration of selected portions of the nose as snoring takes place.
II. Discussion of the Prior Art
In U.S. Pat. No. 5,311,875 to Stasz, which is hereby incorporated by reference, there is described a system for electronically monitoring breathing patterns. The system included a transducer, the active element of which comprises a film of polyvinylidene fluoride (PVDF). As those skilled in the art appreciate, this material exhibits both pyroelectric and piezoelectric properties.
In accordance with the Stasz '875 patent, the transducer was adapted to be mounted on the upper lip of a subject where it would be exposed not only to vibration resulting from snoring but also thermal differences due to respiratory air flow during nasal breathing. The piezoelectric properties of the PVDF film produces a signal proportional to vibration and the pyroelectric properties produces a signal proportional to temperature fluctuations. In a subsequent Stasz et al. U.S. Pat. No. 6,254,545, there is described a combination thermal and vibration sensor for use in sleep monitor equipment where, again, a thin film of PVDF material is the active element. The PVDF film layer is sandwiched between an outer adhesive tape layer and an inner double-sided layer of adhesive tape. The transducer was particularly shaped for placement on the upper lip such that air entering and leaving the nostrils would impinge upon the transducer and so that a further portion is suspended from the upper lip but overhangs the mouth. The contents of the Stasz '545 patent are also hereby incorporated by reference as if set forth in full herein.
U.S. patent application Ser. No. 09/634,148, filed Aug. 8, 2002, which is assigned to the assignee of the present application, describes a vibration transducer based upon PVDF technology where the transducer comprises a generally rectangular patch that is adapted for placement on a subject's throat for the purpose of picking up vibrations caused by snoring.
Experience has shown that while each of the above-described transducer designs successfully operates for its intended purpose, each has its own type of defect that some patients find objectionable. In particular, the Stasz '875 patent and the Stasz et al. '545 patent are designed to be adhesively adhered to a patient's upper lip. If the person that is the subject of a sleep study has a moustache, it becomes somewhat difficult to adhesively affix the transducer to the upper lip and the moustache prevents more intimate contact with the skin of the lip such that vibrations produced by snoring are greatly attenuated. Moreover, subjects have complained about an objectionable tickling response when the transducer is affixed to the upper lip. The transducer that is the subject of pending U.S. application Ser. No. 09/634,148 must be placed at a so-called “sweet spot” on the neck, which is sometimes difficult to locate. In locating it, the subject is asked to hum and while doing so, the technician at the sleep lab must feel about the subject's throat to find the location where the vibration resulting from the hum is a maximum.
It is accordingly a principal object of the present invention to provide a vibration transducer that obviates the drawbacks mentioned above while still providing a robust electrical output signal during episodes of snoring so that information relating to snoring patterns can be discerned.